In the early 1980??s several technical papers were given comparing gear ratings from ISO and AGMA showing some interesting and diverse differences in the trends when the gear geometry was changed slightly. These changes included addendum modification coefficients and helix angle. Differences also existed when the hardness and hardening methods were changed. This paper will use rating programs developed by an AGMA committee to compare AGMA and ISO ratings while having the same gear geometry for both ratings. This will allow consistent trend analysis by only changing one gear geometry parameter while holding other geometry items constant.